【作者】 朱梅；

【导师】 张鹏；

【作者基本信息】 广西工学院 ， 结构工程， 2010， 硕士

【摘要】 为了解决钢筋的锈蚀问题,国内外学者通过研究发现,采用纤维增强塑料筋(FRP)代替钢筋应用的方法行之有效。纤维增强塑料筋(FRP筋)是采用多股连续纤维作为增强纤维,热固性树脂作为基体材料,通过胶合,挤拉固化成型的一种新型复合材料,具有轻质,高强,耐腐蚀,耐疲劳等很多优点,当用于普通混凝土结构时,由于其强度高而强性模量较低,会出现明显的超筋破坏,不安全又难以充分发挥材料性能,因此重点研究CFRP筋在部分预应力混凝土梁中的应用。此外,由于CFRP筋作为预应力筋的粘结方式的不同,使得CFRP筋部分粘结部分预应力梁与相对的CFRP筋全粘结,无粘结部分预应力梁的受弯性能也不尽相同.因此对CFRP筋部分粘结部分预应力混凝土梁受弯性能进行研究。本文在试验研究的基础上,对部分粘结部分预应力CFRP筋混凝土梁受弯性能进行了较为系统的研究,主要进行了以下几方面的工作:(1)通过六根部分粘结部分预应力CFRP筋混凝土梁在单调荷载下的受力全过程试验,对不同无粘结长度的预应力梁试件的受力过程、破坏形态、预应力筋极限应力、极限承载力、延性性能、变形性能等进行较为系统的分析研究。(2)通过系统查阅分析国内外相关CFRP筋部分粘结部分预应力混凝土梁试验研究成果,以及在本文试验研究和非线性有限元模拟分析基础上,对部分粘结部分预应力CFRP筋混凝土梁的正截面承载力(包括预应力筋的极限应力和混凝土梁的极限承载能力),梁的变形性能(包括梁短期刚度和裂缝宽度)进行研究,并给出预应力筋极限应力,梁极限承载力,挠度以及裂缝的设计建议。(3)通过系统查阅分析国内外相关CFRP筋部分粘结部分预应力混凝土梁试验研究成果,以及在本文试验研究和非线性有限元模拟分析基础上,对影响部分预应力部分粘结CFRP筋混凝土梁延性性能相关因素进行研究,其中包括无粘结长度,混凝土强度,有效预应力,预应力度,综合配筋指数以及受压区钢筋的配置等。试验表明,对配置CFRP筋的预应力混凝土梁,采用部分粘结形式,可显著改善梁的延性性能,但随着无粘结长度的增加对梁的延性性能的提高或者降低没有呈现显著而且统一的影响;综合配筋指数对梁延性性能是一个独立的影响参数,随着其值的降低梁变形延性指数升高,并得出综合配筋指数与变形延性指数之间的关系式;在一定范围内混凝土强度的提高,有效预应力的降低,预应力度的提高有利于梁延性性能的提高,反之则不利;认为考虑能量的延性性能指标对于评估试件梁的延性也是适宜的。(4)采用通用有限元软件ANSYS对部分粘结部分预应力CFRP筋混凝土梁在集中荷载作用下的受力性能进行了非线性有限元模拟,对建模方法,单元选取,材料本构关系的定义,求解方法等进行了详细的说明,最后与试验结果进行对比,得到有限元模型的可靠性,为理论分析提供依据。更多还原

【Abstract】 To resolve the problem of rebar corrosion, after many years’study experts have found the application of fiber reinforced plastic(FRP) tendons proved to be the dependable measure in present time. fiber reinforced plastic (FRP) tendon, a new advanced composite material, is formed through pultrusion of epoxy-impregnated reinforced fibers. FRP tendons have many advantages such as lightweight, high strength, corrosive resistance, fatigue resistance, and so on. When used in concrete structure ,it is not very safe and do not make full use of materials strength result in over-reinforced failure .so we pay attention on the application of prestressing FRP tendon using in the partial-prestressed concrete structures.Although, there are many differences between partial-prestressed concrete components with partial-prestressing CFRP tendons and common prestressed concrete components because of tensile stress-strain curve and low young’s modulus of FRP tendons, so does the difference between partial-bonded beam and full-bonded, unbonded ones. so make research on design calculation method and ductility property of the partial-prestressing and partial-bonded CFRP beams.Based on theory and experimental study foundation, has carried on the research to CFRP partial-prestressed partial-bonded concrete number in bending conditioning, the paper focused on following items: (1) six partial bonded concrete beams prestressed with CFRP tendons are tested under monotonic loads. The failure modes, ultimate stresses of prestressing tendons, ultimate load-carrying capacity, ductility, deformation and crack width of this kind of beams with varying unbonded length are systematically investigated.(2) based on the experiments of partial-prestressed partial-bonding concrete beam including CFRP at home and abroad and indignity model in the paper, study on the load-bearing capacity including ultimate stress and ultimate moment-resist capacity. and study on deform capacity including short-time rigid, deflection and width of crack. and offer some design advices.(3) study on influences factors on ductility property of CFRP partial-prestressed partial-bonded concrete beam including the facts such as unbonded length , concrete strength ,PPR, comprehensive reinforcing index, steel fixed in the compressed section and so on.(4) using commercial finite element software, ANSYS, nonlinear finite element simulation of partial-prestressed concrete beams with partial-bonded prestressing CFRP tendons is accomplished. modeling method, selecting element, defining constitutive relationship of materials and solution method that are elaborated on in this paper, and then reliability of methods as mentioned above is testified by comparing with experiment results.更多还原